This invention related to hydraulic water hammer suppressors such as are usually associated with water distribution systems in domestic homes and other buildings.
Generally the construction of such hydraulic suppressors is regulated by governmental codes and these are normally used at each water supply outlet and are frequently located within a wall where they are not readily accessible.
A typical approved suppressor consists of a tube about fourteen inches long having an internal diameter of one inch over the major portion of its length and is adopted for vertical installation in a piping system. The upper end of the tube is closed by a generally conical portion and the lower end is reducd to a one-half inch internal diameter portion about an inch in length through a generally frusto-conical portion about one-half inch in length. The one-half diameter portion is connected into the one-half inch diameter piping system in fluid flow relation. This suppressor construction results from the governmental code which requires a one-half inch piping system. A suppressor consisting of a one-half inch in diameter tube would be of undue length for effective performance and efficient installation. The above-described one inch diameter suppressor reduced to a one-half inch outlet appears to be a satisfactory compromise and my invention is primarily concerned with a suppressor of this construction.
When installed in a piping or distribution system, the air chamber in the suppressor is initially filled with air. When water is caused to flow in the water line, and an outlet is opened, the water flows into the air chamer in accordance with the pressure in the line, compressing the air in the chamber until the compressed air balances in the line pressure. When the outlet is suddenly closed as for example by a quick-closing valve, there is a sudden increase in the line pressure. The shock of this increase in pressure is cushioned by the somewhat compressed air in the suppressor chamber, thus suppressing water hammer. After the initial shock the line pressure stabilizes at the normal line pressure of, for example, 50 psi and the compressed air in the suppressor air chamber balances the line pressure. Under these normal operating conditions the air chamber is always partially filled with water to the extent necessary for the compressed air to balance the water pressure.
In use, even though the system is air and water tight, the air chamber may become water-logged and ineffective due to the gradual absorption of the air therein by the water, especially where well water is used which has a very low air content and because considerable agitation of the water occurs within the air chamber when the valve is closed. It is then necessary to drain the system in order to rejuvenate the suppressor. Also, in summer homes located in wintery climates which are unheated in the winter, it is necessary to drain water systems for the winter. For reasons to be described hereinafter, the air chamber of the suppressor frequently will not drain when the line piping is drained. At present the usual practice is to hammer the suppressor or otherwise physically jar it or the adjacent piping to disturb the forces holding the water in the suppressor. Since the suppressors are frequently located within walls and other inaccessible places this method of draining water hammer suppressors is less than satisfactory.